Yea its a gasser....1995 E320 Wagon. Tried tracing it but it disappears under the plastic drainage vents....no room for a hand or light. I think I'll take your advise and keep the left side of the check valve plugged and just drive it. When I first plugged it everthing appeared to work on the climate contral.....but maybe missed something.

Guess I can always contact MBUSA and see if I can get a Vacuum schematic for my year and model. Haven't had any luck online locating one.

Thanks again!